Conventional vacuum cleaning systems, including conventional upright vacuum cleaners are commonly used in both residential and commercial settings to remove dust, debris and other particulates from floor surfaces, such as carpeting, wood flooring, and linoleum. A typical conventional upright vacuum cleaner includes a wheel-mounted head which includes an intake nozzle positioned close to the floor, a handle that extends upwardly from the head so the user can move the vacuum cleaner along the floor while remaining in a standing or walking position, and a blower or fan. The fan takes in a flow of air and debris through the intake nozzle and directs the flow into a filter bag or receptacle which traps the debris while allowing the air to pass out of the vacuum cleaner. The fan is generally propelled by an electric motor.
Typical upright vacuum cleaners use electric motors that operate at very high revolutions per minute (rpm) such as 25,000 rpm. Although these vacuum cleaners are functional, the high rpm motors impart undesirable qualities to the cleaners. By operating at such high rpm, the motors cause unwanted vibration and noise which greatly detracts from the vacuum cleaning experience. Since gear systems between motors and fans are not customary in vacuum cleaners due to their added weight and size, the fans in these cleaners also spin at high rpm which further contributes to the excessive noise and vibration. As a result these vacuum cleaners hinder normal conversation between humans during operation which raises issues regarding safety among other things. The excessive noise and vibration also can tend to contribute to greater fatigue of the vacuum cleaner operator.
An optimal low rpm motor for applications such as vacuum cleaners, yard blowers, floor buffers, and extractors for carpets and floors, must also be compact, light weight, produce little heat, and have high torque output as well as operate at a low rpm. Prior attempts at designing such motors have experienced many problems in arriving at an effective combination of these attributes. For instance, relatively cooler running motors have typically been heavy having extra thermal mass. Other high torque motors have been too bulky for effective use in these devices. Given this lack an effective combination of attributes, the typical prior art motors in such devices as vacuum cleaners, air cleaners, yard blowers, floor buffers, and extractors for carpets and floors have remained low torque, high rpm despite the inherent noise and vibration problems involved.